1. Field of the Invention
The invention relates to a method of forming a line pattern, and more particularly, to a method of forming a line pattern through a directed self-assembly (DSA) process.
2. Description of the Prior Art
Conventional lithography techniques used in the fabrication of semiconductor devices include the double patterning technique by argon fluoride (ArF) immersion exposure, extreme ultraviolet (EUV) lithography, and nano imprints. However, as the size of semiconductor devices is continuously shrunk, such conventional lithography techniques face more limitations in the fabricating process, such as increased costs and decreased throughput caused by the refinement of patterns.
Under such microminiaturized demands, application of directed self-assembly (DSA) materials to lithography techniques is expected. Since directed self-assembly is generated by spontaneous energy stability, this enables the formation of patterns with high dimensional accuracy. Especially for technologies using microphase separation of macromolecule block copolymer, periodic structures up to several hundred nanometers (nm) of various shapes may be formed with a simple coating and annealing process. Depending on the composition ratio of the macromolecule block copolymer, spherical shapes, cylindrical shapes, or lamellar shapes may be formed by changing the sizes based on the molecular weight, and a dot pattern, hole or pillar pattern, or a line pattern of various dimensions may be formed on a substrate.